Thanks to Prof Hwang for being a great teacher.Ejs open source Vernier calipers applet with many options for smallest division

This is an EJS version of vernier caliper with option for positive or negative zero error for faulty caliper(Adjust the vertical slider up/down).Click the checkbox to find out the base unit and the correct value.You can select different type of vernier caliper,too (from the selection list).

Vernier calipersVernier calipers can measure internal dimensions (using the uppermost jaws in the picture at right), external dimensions using the pictured lower jaws, and depending on the manufacturer, depth measurements by the use of a probe that is attached to the movable head and slides along the centre of the body. This probe is slender and can get into deep grooves that may prove difficult for other measuring tools. The vernier scales can be in metric measurements on the upper and lower part of the scale.Vernier calipers commonly used in industry provide a precision to a hundredth of a millimetre (10 micrometres). A more precise instrument used for the same purpose is the micrometer

.Parts of a vernier caliper:Outside jaws: used to measure external diameter or width of an object (Blue) Inside jaws: used to measure internal diameter of an objectDepth probe: used to measure depths of an object or a hole ( not shown in this model) Main scale: gives measurements in mm.Vernier gives measurements up to one decimal places in mmRetainer: used to block movable part to allow the easy transferring a measurement ( not shown in this model)The Vernier calipers model has an object (Blue) for the internal jaws to measure width of an object with slider to control width of the object and simple drag action to control position of object.an object (Green) for external jaws to measure internal diameter of a cylinder for example with slider to control dimensions of the cylinder.a slider for zero error slidercheckbox for hint to scaffold the learners attention and point of focuscheckbox for answer to show the meaning of reading on the main scale and the vernier scale with zero error calculations if any.drop down menu of the various common vernier scales for sense making and additional testing out by learners their ideas of how vernier works.fine <> control buttons for learners to manipulate the model with single incremental precisionslider control for fast changes in the vernier measurementreset button to bring simulaton back to original (default) setting.

A youtube video made to spread the news of learning by doing & exploring sense making physics.

Modifications done are:1. cant remember nowJune 03 200934. left and right button for fine control of slider35. added scaffolds of the hints to be more meaningful, show exactly the difficult cases of understanding the reading with zero errors36. added the final answer also to display the logic of how the top scale + lower scale + error.37. fool prove it to work even for difficult cases the scaffolds are dynamically displayedJuly 23 200938. added autoscale for hard to see scaffolds39. change the text to the new version in Ejs 4.1 pixel size = true for nicer displaySeptember 08 200940. added object blue for internal jaws with proper constraints and push if touch and slider control41. added green object for external jaws with slider control42. redesigned the scaffolds for the zero error to reflect correctly the logic of reading with zero error43. sync the pointers position to correctly reflect the zero error calculation44. redesign the zero error slider to show 0.05mm instead of e=1 increment to be easily to understand45. redesign the look and feel of the controls and the color scheme so it is easier to read white top scale on darkgrey top scale and light color bottom scale on black lines.46. all new objects in Ejs 4.2 instead of the older objects drawing originally12Sept 200947 fix bug due to 0.08 being read as 0.05 instead of 0.1 if the marking are 0, 0.05 0.1. by hwang @ http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=567.3018Sept 200948. added html and png to description49. added comments to all variables for ease of open source sharing18Nov200950 found a bug created by the pointer vss when l_x = 15.00 mm = 14.00+0.00 mm instead of the correct 15.00+0.00 caused by the slider value not 14.999999999 going to 14 and fixed it by using codevss = (int)((x/dxm+error*unit+1.e-2)); // introduce to point to include zero error and debug need + 1.e-2 for cases where there may be error is calculation51 fixed more bug with 2.e-2 for text1 and vss52 added text input field for learner to test their understanding http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1309.0 thanks to prof hwang. It has the input field for student checking their understanding especially useful for learning the importance of precision of measurement. This is because 19.40 mm is precise, 19.450 mm is too precise and 19.4 mm is not precise enough for the vernier caliper of smallest unit 0.01 mm.29Nov200953 made it possible to select either external jaws use ( example diameter of green object) or internal jaws (example use on external dimensions of blue rectangle)

54 made the vernier caliper behavior more like a real life one with some boundary detection that works well if lightly pressed like in real life? http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1313.055 it is possible by accident to over-compressed the blue object for teachable moments with the students to illustrate inappropriate use of vernier caliper 56 possible to over force blue object into be vernier caliper like in 3D z direction, but it should work nicely if the movement of the mouse on drag is gentle!57 used prof hwang's code in blue object on drag and made the blue object behave determistically so 54-55-56 is not going to in future release of the applet, if u r looking for that, download the version 4 at the bottom post.58 fixed an array out of bound discovered by wolfgang error http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1183.msg5076;topicseen#msg507659 fixed another array runtime error when slider is drag to 70.00mm and beyond60 made the yellow slider and vernier scale max slide to 69.80 mm to avoid over drag to very large values which is surprising possible, the applet still is measuring. 07March201061 added depth stem and object for simulating measurement on objects like test-tube, thanks Prof Hwang inspiration to http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1408.0 vernier cliper (inch/mm mode, dial mode, measure inner/outer diameter and depth)13june201062 made the dimension of web applet width = 600 to fit http://sgeducation.blogspot.com/2010/06/ejs-open-source-vernier-calipers-java.html26june201063 made the x max view bigger to include part of the depth probe of the vernier caliper64 made autoscale==true when the depth probe is selected21 july 2011added zoom for close up view of the vernier scale on the main scale27july 2011fixed bug where 0.02mm is selected the hints is 11.98 mm is shown as 12.00 + .98 mm the top pointer jump ahead due to a code

new post 20Jan 2009i notice a display bug but i can't figure out what is causing it. prof hwang any thought?

open source codes and creative commons attribute

source code download the *.jar for using the applet on standalone without internet connection.

31 october 2011redo the zoom into a similar magnify just like the micrometer thanks to ability to draw students attention to the lines based on codes from http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=2268.0 by Fu-Kwun Hwangrandomize the size of the black object each time to simulation is reset for greater challenge and fun

I guess the initial value for the distance d was set to 0.And the applet will calculate new value and change displayed value when user drag it (several related values are changed,too.)However, when you change the initial value to other value, but did not change the displayed String. How to fix it:method 1: change initial value for the display string.method 2: add the function to be called when use drag the mouse to the initialization page.

This is definitely the applet that I was looking for. I am still having difficulty obtaining this file. I am looking to use the app as is for educational purposes. However, I am still having difficulty with the jar file. Any suggestions?

I just clicked Download EJS jar file and save it on my computer.It is running fine with my computer. Because I do not know what you did and what was happening. I do not know how to help you if you just said that you have difficulty getting the file without further information.Did you find the download link? Did you doenload it? What is the file size and filename of the downloaded file? ...

This is definitely the applet that I was looking for. I am still having difficulty obtaining this file. I am looking to use the app as is for educational purposes. However, I am still having difficulty with the jar file. Any suggestions?

Thanks for ur encouragement, Fu-Kwun Hwang made this, i merely remixed it to be more customized for self directed inquiry learning.

check the new Ejs open source Vernier calipers java applet with objects and zero error logic.

September 08 200940. added object blue for internal jaws with proper constraints and push if touch and slider control http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=118941. added green object for external jaws with slider control http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=118942. redesigned the scaffolds for the zero error to reflect correctly the logic of reading with zero error43. sync the pointers position to correctly reflect the zero error calculation44. redesign the zero error slider to show 0.05mm instead of e=1 increment to be easier to understand45. redesign the look and feel of the controls and the color scheme so it is easier to read white top scale on darkgrey top scale and light color bottom scale on black lines.46. all new objects in Ejs 4.2 instead of the older objects drawing originally

it is most educational with inquiry possibilities now! thanks prof hwang for your tips!check it out.

A youtube video made to spread the news of learning by doing & exploring sense making physics.

Music is audio swapped by Youtube in built service. cool I am assuming Youtube asked for permission already to use the music for youtube users.

I believe this is applicable to me. * * Tell me. I may not get it, I'm sure to forget it. * * Show me. I may get it, I'll remember it for a little while. * * Have me do it. I'll understand it, it may stick for awhile.

got a suggestion from wolfgang1 .you should not be able to move the block inside the jaws if jaws the jars are too close together. 2. I select either internal or external measurement with a check box and would hide the internal object if external is selected and hide the external if internal is selected.

my reflection:need time to think how to do it having some difficulty thinking about the interaction modeling

if ( ox>=(x2+x-w/2)&&(oy>oymin-h/2)&&(w>x)) { // >= is important not == does not work well // recently added w>x still cannot get the interaction of suggestion1 x = ox -x2 +w/2; // to make object and jaw right move together when touched}

53 made it possible to select either external jaws use ( example diameter of green object) or internal jaws (example use on external dimensions of blue rectangle) 54 made the vernier caliper behavior more like a real life one with some boundary detection that works well if lightly pressed like in real life? http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1313.055 it is possible by accident to over-compressed the blue object for teachable moments with the students to illustrate inappropriate use of vernier caliper Grin56 possible to over force blue object into be vernier caliper like in 3D z direction, but it should work nicely if the movement of the mouse on drag is gentle!

Thanks you for posting your good comments about this applet.It is always improving based on prof hwang's several different applets on the same topic plus I ask some questions about how to do Some pedagogy hints and input fields to get students to test their understanding.

Java appletsI was greatly impressed by your micrometer and ruler applets and would like to host them on my website. Unfortunately the links you provide are dead. When possible, could you please drop message for me where could I get the applets. I would need a source code as well under any Free license of your choice. Audriusa (talk) 12:27, 18 July 2010 (UTC)User talk:AudriusaFrom Wikimedia Commons, the free media repository